This invention relates to a method for preparing para-divinylbenzene (PDVB) by dehydrogenating para-diethylbenzene (PDEB) followed by crystallization of para-divinylbenzene.
Divinylbenzene (DVB) is a very reactive monomer which may be used for polymers or as a crosslinking agent for copolymers. Divinylbenzene is presently available as a 40/60 para/meta mixture. This mixture is produced by dehydrogenation of the corresponding diethylbenzene (DEB) mixture. The latter can be produced by an alkylation with AlCl.sub.3 /HCl to give all three diethylbenzene isomers.
Purification of this divinylbenzene mixture by distillation is impractical because of the high temperatures required and sensitivity to polymerization. Furthermore, these isomers cannot be separated by fractional crystallization, when in admixture in such proportions.